Internal conversion

As Internal Conversion ( engl.: internal conversion, IC) is a special case of the radioactivity is called in physics, is related to the gamma decay. The energy that is released during the transition of the atomic nucleus to a lower excited state, it goes beyond (the " conversion electron" ) by direct electromagnetic interaction on an orbital electron. The electron is thus removed from the atom, and the atom remains positively charged ion.

Type of interaction

It is in the internal conversion is not a two-stage process in which the nucleus first emits a gamma quantum and this then passes through the shock energy to an orbital electron. This is demonstrated experimentally that the conversion electrons are also observed in transitions, where not possible ( " forbidden ") because of conservation of angular momentum gamma emission. Examples include the double magic nuclides oxygen -16 and calcium -40, in which the first excited state to the ground state, as well as the magnetic zero and positive parity is such that no gamma ray may be emitted.

Energy spectrum of conversion electrons

The kinetic energy Ee of emitted conversion electron is the difference between the core in the released energy Eγ and different depending on shell binding energy EB of the electron:

The conversion electrons thus show unlike electrons from the beta decay, a line spectrum. Depending on whether the electron is bound in the K-, L- shell, etc., it is called K-, L-, etc. - conversion.

Decay probability

As an alternative to the internal conversion occurs gamma emission, the entire probability of decay of the initial core state per unit of time is the sum of the two individual probabilities:

As the electron, the internal conversion is generally considered as a kind of radioactivity. However, in addition to the intrinsic properties of the Kernisomers their probability also depends on conditions of the shell, ie the probability of the electrons at the nucleus. The half-life can thus be influenced by changing the chemical bonding of the atom. Experimental changes were observed up to the order percent.